Roll-on dispenser balls

ABSTRACT

The present invention relates to roll-on dispenser balls. The roll-on dispenser balls may be used as is known in the art, including, for example, for use as a component or part of a dispenser of a liquid cosmetic (such as a deodorant) having a revolving ball as an applicator. The disclosed roll-on dispenser balls provide advantages over the prior art, such as, but not limited to, the lack of weld lines or joints in the finished product. Methods of producing the disclosed roll-on dispenser balls and apparatus for use in producing the disclosed roll-on dispenser balls are also provided.

The present invention relates to roll-on dispenser balls, for example deodorant balls, and methods of producing such balls. The term “roll-on dispenser ball” is intended to mean a ball which may form part of a “roll-on” dispenser i.e. a dispenser of a liquid cosmetic (such as a deodorant) having a revolving ball as an applicator.

According to an aspect of the present invention there is provided a roto-moulded roll-on applicator ball.

Rotational moulding, also called roto-moulding or rotocast, is a thermoplastic process for producing hollow parts by placing powder or liquid resin into a hollow mould and then rotating bi-axially and heating until the resin melts and coats the inside of the mould cavity; next the tool is cooled and the part is removed from the mould.

There may be four steps in manufacturing a rotational moulded ball:

1. Fill the mould with a polymer material

2. Heat the mould to melt material and rotate to form the ball by coating the interior surface of the mould

3. Cool the mould to solidify the ball

4. Remove the ball from the mould

A further aspect provides a roto-moulded deodorant ball.

A further aspect provides a roll-on applicator comprising a ball as described herein.

A further aspect provides a method of forming a roll-on applicator ball comprising the steps of:

-   -   a mould (for example formed from two halves) gets filled with         thermoplastic material (such as PP or PE) according to the         target weight     -   the mould is mounted together     -   the rotation of the mould will go over two or more axes, for         example over the centre points of the ball     -   after rotation has started, the mould is heated to a temperature         that allows the resin to plastify     -   when plastifying is finished, the mould will get cooled, still         whilst rotating     -   after cooling the mould is opened and ball can be taken out.

In some embodiments the raw material used to form the ball is powder. Other embodiments may use, for example, small pellets, flakes or other ground material.

A further aspect provides a method of forming a roll-on applicator ball comprising the steps of:

-   -   providing a mould with a generally spherical cavity;     -   introducing a portion of thermoplastics material into the mould;     -   rotating and heating the mould;     -   cooling the mould; and     -   removing a formed ball from the mould.

The balls may be formed, for example, from a thermoplastics material such as polyethylene or polypropylene.

Example target weights for a 1.4 inch diameter ball: 1 g to 6 g, for example 1.5 g to 5.5 g, for example approximately 2.0 g to 3.5 g.

Target weights for balls from 0.8 up to 2.0 inch (for example 1.0 inch, 1.14 inch, 1.3 inch and 1.4 inch) varying from 1 g up to 6 g.

For other ball sizes similar lower weights in relation to diameter.

According to an embodiment of the invention a method of forming a ball comprises the following steps:

-   -   a mould (two halves) gets filled with thermoplastic resin         powder, according to the target weight     -   the mould is mounted together     -   the rotation of the mould will go over one or more axes, for         example two axes over the centre points of the ball     -   after rotation has started, the mould is heated to a temperature         that allows the thermoplastic material to plastify     -   when plastifying is finished, the mould will get cooled, still         whilst rotating     -   after cooling the mould is opened and ball can be taken out

With multi-cavity moulds, the rotation may go over the two middle axis (vertical and horizontal) of the roto mould.

Different heating systems may be used, for example: heating, heating in an oven, hot air, infra-red lights, inside heater/s, induction heater.

The rotation may comprise turning in 2 or more axes of the centre of the ball. In other embodiments the rotation may comprise turning in 2 or more axes not over the centre of the ball.

Advantages of the rotomoulding process include:

-   -   no weld line in the deodorant balls     -   no stress inside the parts     -   quality of balls very good, because of no weld line     -   grinding time of raw balls will be further minimised     -   strength of the ball on static load very good

The present invention also provides a moulding machine comprising one or more moulding tools as described herein.

Roll-on balls manufactured in accordance with the present invention are formed without a weld or joint.

Currently the manufacturing process of a roll on ball requires: producing the ball;

rough grinding; and fine grinding.

The rough grinding is a long and costly process the requirement for which is removed by the present invention.

Balls formed in accordance with the present invention may have a wall thickness in the range 0.1 mm to 1 mm, for example 0.2 mm to 0.8 mm.

Different aspects and embodiments of the invention may be used separately or together.

Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with the features of the independent claims as appropriate, and in combination other than those explicitly set out in the claims.

The present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a moulding tool formed according to the present invention;

FIG. 2 is a further perspective view of the tool of FIG. 1;

FIG. 3 is a section of the tool of FIG. 2;

FIG. 4 is a photograph of a tool of the type shown in FIGS. 1 to 3;

FIG. 5 is an additional photograph of a tool of the type shown in FIGS. 1 to 3;

FIG. 6 shows the tool of FIGS. 4 and 5 supported on a mount;

FIG. 7 shows an additional illustration of the tool of FIGS. 4 to 5 supported on a mount;

FIG. 8 shows a further additional illustration of the tool of FIGS. 4 to 5 supported on a mount;

FIG. 9 shows the tool of FIGS. 4 to 8 with a mould in an open position;

FIG. 10 shows an addition illustration of the tool of FIGS. 4 to 8 with the mould in an open position.

FIG. 11 is a perspective view of a multi-cavity rotomould formed in accordance with the present invention;

FIG. 12 shows the rotomould of FIG. 1 with one half of one side of the mould cut away for illustration purposes;

FIG. 13 shows a perspective view of the rotomould of FIGS. 11 and 12;

FIG. 14 shows a side view of the rotomould of FIGS. 11 and 12;

FIG. 15 shows a plan view of the rotomould of FIGS. 11 and 12;

FIG. 16 shows an additional perspective view of the rotomould of FIGS. 11 and 12;

FIG. 17 shows an end view of the rotomould of FIGS. 11 and 12; and

FIG. 18 shows a rotomoulded ball formed in accordance with the present invention.

Example embodiments are described below in sufficient detail to enable those of ordinary skill in the art to embody and implement the systems and processes herein described. It is important to understand that embodiments can be provided in many alternate forms and should not be construed as limited to the examples set forth herein.

Accordingly, while embodiments can be modified in various ways and take on various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below as examples. There is no intent to limit to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included. Elements of the example embodiments are consistently denoted by the same reference numerals throughout the drawings and detailed description where appropriate.

The terminology used herein to describe embodiments is not intended to limit the scope. The articles “a,” “an,” and “the” are singular in that they have a single referent, however the use of the singular form in the present document should not preclude the presence of more than one referent. In other words, elements referred to in the singular can number one or more, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, items, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, items, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein are to be interpreted as is customary in the art. It will be further understood that terms in common usage should also be interpreted as is customary in the relevant art and not in an idealized or overly formal sense unless expressly so defined herein.

Referring first to FIGS. 1 to 3 there is shown a moulding tool generally indicated 10.

The tool 10 comprises a shaft 15 which carries a head 20. The head is generally U-shape, having a base 21 and a pair of spaced uprights 22, 23 which extend from the base 21.

The shaft 15 comprises an outer sleeve 25 and an inner shaft 30. The outer sleeve is fixed to the head can be rotated to co-rotate with the head 20. The inner shaft 30 can rotate within the outer sleeve 25. The inner shaft 30 is rotatably connected to a first gear wheel 35 provided on the head 20.

The first gear wheel 35 meshes with a second gear wheel 40 orientated orthogonally to the first gear wheel 35.

The second gear wheel 40 supports a mould shaft 45. The mould shaft 45 is formed in two parts: a first shaft part 46 is rotatably received in the upright 22 and a second shaft part 47 is rotatably received in the upright 23.

Each shaft part 46, 47 is provided with a hemispherical mould half 48, 49 at one end. The mould halves 48, 49 fit together to form a mould 50 with aspherical mould cavity 55.

In use material is loaded into either or both of the mould halves 48, 49 and the halves are brought together as shown in the drawings. The shaft 15 is rotated, which rotates the head 20. In addition the shaft 30 is rotated within the sleeve 25. This causes the first gear wheel 35 to rotate which in turn causes the second gear wheel 40 to rotate; consequently the mould shaft 45 rotates to spin the mould 50 (in a direction orthogonal to the spin of the shaft 15) so that the mould is rotated along two axes.

At the same time the mould is rotated heat is applied to melt the material. Gravity causes the melted material to be thrown to the internal surface of the mould cavity.

The plastic particles make contact and melt on the inner surfaces of the hot moulds and fuse in layers until all the powder is fused and the desired end product and wall thickness is obtained. The wall thickness is controlled by the amount of powder placed in the mould.

Rigid, resilient hollow bodies are thereby formed by powdered plastic material in heated moulds which are rotated simultaneously in two planes perpendicular to each other.

The mould 50 is then cooled, in this embodiment whilst it is still being rotated. Rotation then stops and the mould can be opened to reveal a spherical, hollow ball.

In a further embodiment the method of forming a ball includes the following steps:

-   -   A mould (two halves) gets filled with PP powder, according to         the target weight     -   The mould is mounted together     -   The rotation of the mould will go over two or more axes,         currently over the centre points of the ball     -   After rotation has started, the mould is heated to a temperature         that allows the thermoplastic material to plastify     -   The material coats the interior of the mould cavity,     -   The mould will get cooled, still when rotating     -   After cooling mould is opened and ball can be taken out

In FIGS. 4 and 5 a moulding tool 110 formed according to a further embodiment is shown.

In FIGS. 6 to 8 the tool 110 is shown rotatably mounted on a support structure 160.

In FIGS. 9 and 10 the mould 150 is shown opened, with the two mould halves 148, 149 separated.

FIGS. 11 to 17 show a multi-cavity rotomould tool generally indicated 270.

The tool 270 comprises a main tool body 272 within which are formed four mould bays 274 a-d. Each bay 274 a-d has a spherical mould 275 a-d.

In this embodiment the moulds 275 a-d undergo biaxial rotation, with rotation going over the two middle axes (vertical and horizontal) of the roto mould.

FIG. 18 shows a generally spherical roto moulded ball 300 formed in accordance with the present invention. The ball 300 has no joints of weld zones, being formed as a single-piece ball.

Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiments shown and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention. 

1. A roto-moulded roll-on applicator ball.
 2. A ball as claimed in claim 1, in which the ball is a deodorant ball.
 3. A ball as claimed in claim 1 formed in the absence of joints or welding zones.
 4. A ball as claimed in claim 1, in which the weight of the ball is in the range 1 g to 6 g.
 5. A ball as claimed in claim 4, in which the weight of the ball is in the range 1.5 g to 5.5 g.
 6. A ball as claimed in claim 5, in which the weight of the ball is in the range 2.0 g to 3.5 g.
 7. A ball as claimed in claim 1, in which the diameter of the ball is in the range 0.8 to 2.0 inches.
 8. A ball as claimed in claim 7, in which the diameter of the ball is 1.0 inch, 1.14 inch, 1.3 inch or 1.4 inch.
 9. A ball as claimed in claim 1, in which the ball has a wall thickness in the range 0.1 mm to 1 mm.
 10. A ball as claimed in claim 9, in which the ball has a wall thickness in the range 0.2 mm to 0.8 mm.
 11. A roll-on applicator comprising a ball as claimed in claim
 1. 12. A method of forming a roll-on applicator ball comprising the steps of: providing a mould with a generally spherical cavity; introducing a predetermined quantity of thermoplastics material into the mould; rotating and heating the mould to cause material to melt and completely coat the internal surface of the cavity; cooling the mould; and removing a formed ball from the mould.
 13. A method as claimed in claim 12, in which the rotation of the mould goes over one or more axes.
 14. A method as claimed in claim 12, in which the mould is rotated simultaneously in two planes which are generally perpendicular to each other. 